This is the renewal application for Years 21-25 of a training program designed to produce investigators at the cutting edge of research in the area of pediatric gastroenterology (GI). Trainees will be at the postdoctoral level and a mixture of MDs supported for 3 years and PhDs supported for 2 years for a total request of 5 stipends/yr. to accomplish these goals. The program traditionally has placed strong emphasis on molecular biology, the rationale being that molecular approaches are of central importance in both study and treatment of diseases associated with pediatric GI. In the current proposal there is also emphasis on bringing the results of molecular research to the bedside with opportunities for intense training in clinical research. The mentors (7 MDs, 2 MD/PhDs and 10 PhDs) represent a multidisciplinary group of experienced investigators from various departments at Baylor College of Medicine (BCM), the University of Texas Health Science Center, and the MD Anderson Cancer Center. Their research covers four broad areas that are important to pediatric GI, namely: mucosal biology, molecular hepatology, immunology and inflammation, and translational biology. All mentor laboratories are well funded and well equipped. Existing faculty members (17 of 19) have excellent track records of interaction and participation in our training program activities. The two new faculty members have outstanding mentoring histories. The Program Director, Robert J. Shulman, MD maintains ultimate authority for the program and manages day-to-day operations. He is assisted by an Associate Program Director (Douglas G. Burrin, PhD for additional expertise in basic science research). Major administrative decisions (e.g., selection of trainees) are handled by an Executive Committee, which includes the Program Director, Associate Director, three other program faculty, and a senior faculty member not associated with this grant. The training program for MD fellows includes research rotations to facilitate selection of a mentor. Both MD and PhD trainees have individual research committees, must prepare a written research proposal to be defended to the research committee, and have periodic reviews that include academic and career assessment. Both MD and PhD fellows are required to attend a biweekly research seminar series, a monthly journal club, and a thrice yearly scientific social. All trainees (MD and PhD) must present at these meetings. Trainees are selected from a highly competitive applicant pool that already exists at BCM. Over the past 10 years trainees have performed well with 80% of MDs and 100% of PhDs remaining in academia. The majority of these have been successful in securing either internal or external funding for their research including R01, K08, K01, and R21 grants, as well as from other competitive sources. The current proposal includes several new features designed to enrich and enhance the existing program including: 3 years of research training for all MDs, a Clinical Scientist Training Program for MD trainees intent on a clinical research career, and for PhDs trainees, interactions with the interdepartmental Graduate Program in Translational Biology &Molecular Medicine.